A hydroelectric dam converts potential energy, stored in the water at an elevated position, into electricity through a process that involves the following steps:
Water Reservoir: A dam is built across a river or a waterway to create a reservoir or an artificial lake. The reservoir is located at a higher elevation than the downstream area.
Penstock: A large pipe or conduit called a penstock is connected to the reservoir. The penstock serves as a channel to direct the water flow from the reservoir to the turbine.
Turbine: At the end of the penstock, there is a turbine, a large wheel with blades. As the water from the reservoir flows through the penstock and reaches the turbine, it applies force to the blades of the turbine, causing it to spin.
Generator: Connected to the same shaft as the turbine is a generator. The spinning motion of the turbine is transferred to the generator, which consists of a coil of wire and magnets. This motion induces a flow of electric current in the wire coils through electromagnetic induction.
Electricity Generation: The flow of electric current in the wire coils of the generator produces electricity. This electricity is then transmitted through power lines to homes, industries, and other locations where it can be used to power electrical devices and systems.
Outlet and Tailrace: After passing through the turbine, the water exits through an outlet called the tailrace and returns to the downstream river or waterway. The energy it had as potential energy in the reservoir is now converted into kinetic energy as it flows through the penstock and spins the turbine.
This process of converting potential energy in water at an elevated position into kinetic energy and then into electricity is known as hydroelectric power generation. Hydroelectric power is a renewable and sustainable energy source since it relies on the natural water cycle, and the generation process does not involve the combustion of fossil fuels, thereby producing minimal greenhouse gas emissions.